In two articles in the previous volume of this journal, Clifford J. Rogers and Trevor Russell Smith offered new transcriptions and translations of several nearly unknown gunpowder recipes from the last hundred years of the Middle Ages. Rogers noted that there were very few complete recipes for gunpowder proper (that is, for mixtures specifically intended to propel projectiles from guns) that could be reliably dated to the first fifty years of the history of cannon in Europe (1326–1375). In fact, since the recipes in the Munich copy of the Büchsenmeisterbuch (MS. Cgm 600) probably date to around 1400 (rather than c. 1350, as once thought), and since the French “recipes” of c. 1338, 1345, and 1350 are actually purchase records rather than instructions for manufacture, and moreover do not specify the proportion of charcoal to be used,3 that left only one such recipe known to scholars of early artillery: one from Augsburg, composed not long after 1337. That one recipe, moreover, is sufficiently ambiguous that different scholars have read it in two different ways, leaving the earliest history of cannon-powder very unclear. It is now possible to expand the roster from one to two, adding an even earlier formulation: one written down in northern Italy in 1336. Comparison to this earlier recipe, in combination with laboratory testing, makes clear which reading of the German recipe is correct. The combination of the two recipes, correctly interpreted, gives us a good picture of the earliest cannon-powders, which were by modern standards low in saltpeter and high in sulfur.

THE ST OMER CHRONICLE, the focus of this study, is an anonymous contemporary narrative of around 21,000 words that deals almost exclusively with the conduct of the Hundred Years’ War in the period 1342–47. During these five years, the English enjoyed an astounding degree of military success. Although France had triple the population and wealth of England, a high martial reputation, and the aid of Scotland, Edward III and his lieutenants were victorious in every theater. In the southwest of France, Henry of Lancaster crushed two French field armies, at Bergerac and Auberoche; captured dozens of magnates whose ransoms, collectively, far exceeded the peacetime annual revenues of the English crown; seized control of 136 castles and towns, including major centers like La Réole, Bergerac, and Poitiers, strategically crucial places like Aiguillon, and exceptionally strong fortresses like Lusignan; and won his reputation as “one of the best warriors in the world.” In Brittany, Edward III pushed the zone of English control, which at one point hardly extended past the walls of Quimperlé, as far east as the vicinity of Vannes. His lieutenant Sir Thomas Dagworth, with small forces at his disposal, was nonetheless able to more than hold his own against a major French counter- thrust. First, he won a small engagement at Restellou near Kergadoret that Sir Thomas Gray considered the most marvelous victory of the Breton Wars. Then he triumphed in a much more significant battle at La Roche Derrien, where the pro-Valois claimant to the duchy, Charles of Blois, was captured. On the Scottish front, the English thoroughly defeated a royal army led by David II, and brought the wounded king of Scots himself to the Tower of London as a prisoner. Meanwhile Edward III ravaged Normandy from the Cotentin to the Seine, sacked the large city of Caen and dozens of smaller towns, burned the royal palace of Montjoye outside Paris, and won the great battle of Crécy. Then, after keeping an army on French soil for over a year, he captured the key strategic port of Calais, so that, as Froissart put it, thereafter the English considered that “the keys to the kingdom of France hung at their belt.”

The St Omer Chronicle is an important source for nearly all of these major operations – but then, so are several other chronicles.

Few technological innovations have been as momentous as the development of gunpowder. Gunpowder was the first major harnessing of chemical energy by humans since the mastery of fire, and the development of gunpowder artillery has been commonly used since the eighteenth century as the original and archetypical example of a “military revolution.” Whether cannon actually did “revolutionize” warfare is a debated subject, but most of those who argue that it did do so date the Artillery Revolution to some time in the first half of the fifteenth century. By then, however, gunpowder artillery had been in use for around a century. Our sources allow us a reasonably good understanding of the development of guns during the fifteenth century, but our information about the fourteenth century (especially in the first fifty years, from c.1326 to c.1375) is relatively thin.

The same is true of the development of gunpowder. All gunpowder includes a mix of saltpeter, sulfur, and charcoal. Nineteenth-century gunpowder was typically mixed with ratios of around 75:10:15 (in that order), i.e. with a saltpeter:sulfur ratio of 7.5:1 and a saltpeter content of 75%. Several early fifteenth-century recipes come fairly close to that mix, though some have significantly more sulfur content. A recipe from Montauban of the turn of the fifteenth century calls for 22:4:5 (71%/13%/16%). One of the two Frankfurter Büchsenmeisterblätter recipes (c.1400) gives a ratio 5:1:1 (71%/14%/14%). The 1405 manuscript of Bellifortis includes a 4:1:0.5 (73%/18%/9%) mix; the Büchsenmeisterbuch (composed at an uncertain date before 1411, probably around 1400) recommends the same mixture with small additions of salarmoniac (ammonium chloride) and salpracticum (a mix of saltpeter and salarmoniac), or 3.5:1:0.5 (70%/20%/10%) without those extra ingredients. Abundant evidence shows a shift towards – or back towards – somewhat lower saltpeter content in later fifteenth-century recipes, including those edited by Trevor Russell Smith in the following article in this volume of the Journal of Medieval Military History.